Blockade of the CCL2-CCR2 axis attenuates fibrosis and parasite load in vesicular echinococcosis by inhibiting the PI3K-AKT pathway that regulates angiogenesis and hepatic stellate cell apoptosis.

BACKGROUND: The C-C motif chemokine ligand 2 (CCL2)-C-C chemokine receptor type 2 (CCR2) signaling axis is critically involved in angiogenesis and cellular invasion; however, the therapeutic potential of its targeted blockade on alveolar echinococcosis (AE) remains largely unexplored. This study aimed to determine whether RS504393, a selective CCR2 antagonist, can inhibit the progression of AE by blocking the CCL2-CCR2 axis and modulating its downstream pathogenic mechanisms.

METHODS: In this study, bioinformatics analysis of the GSE124362 dataset was combined with molecular docking simulations. Liver tissues from patients with AE and from Echinococcus multilocularis-infected mice were examined through histopathological and immunohistochemical staining methods. Pathological alterations and parasitic load were assessed by Western blot and quantitative real-time PCR (RT-PCR). An in vitro co-culture model involving Echinococcus multilocularis protoscolex-stimulated endothelial progenitor cells (EPCs), JS1 hepatic stellate cells (JS1) and RAW264.7 macrophages was established to evaluate angiogenesis, fibrogenic activity and macrophage polarization.

RESULTS: Integrated bioinformatics and molecular docking analyses revealed CCL2-CCR2 overexpression and high-affinity binding during AE progression. Treatment with RS504393 significantly attenuated hepatic fibrosis, suppressed phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) pathway activation and reduced M2 macrophage polarization in central lesion tissue of E. multilocularis-infected mice . In vitro, RS504393 inhibited angiogenesis driven by EPCs, induced apoptosis in JS1 cells, and redirected macrophage polarization from the M2 towards a more anti-parasitic phenotype.

CONCLUSIONS: CCR2 blockade with RS504393 attenuates AE progression by inhibiting PI3K-AKT signaling, suppressing angiogenesis and inducing stellate cell apoptosis, collectively reducing hepatic fibrosis and parasitic burden. Our findings provide a mechanistic rationale for repurposing CCR2 antagonists as a novel host-directed therapeutic strategy for echinococcosis.